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This paper is a continuation of SAE-Paper 2005-01-0222 presented at the 2005 SAE World Congress, denoted Part 1 in this text. In Part 1 three turbines were selected from calculations and three manifolds with different geometries were designed. This paper, Part 2, covers the results from engine-simulations and measurements on these nine different combinations of turbines and manifolds. It was shown that the possibility of maintaining isentropic power was the most important property, overshadowing any differences in turbine efficiency. The isentropic power was inversely dependent on both manifold volume and turbine throat area. The GT-Power models of all nine setups were calibrated against the measured data. The need for efficiency and massflow multipliers is described. The efficiency multiplier depended on mass flow through the turbine, with a distinct minimum value (0.7-0.8) around 0.03 kg/s and higher around that.

In this study, the transient response of a turbocharged engine is minimized by using 1D engine simulation. A method is developed where sequential fractional factorial designs are utilized to first determine the relative importance between a wide range of design parameters and then successively come closer to an optimal setup for minimized transient response. This methodology is first developed and applied to a 2-liter standard production car engine and then it is used for optimization of the 2004 KTH Racing Formula Student engine. The race engine was first designed entirely by using steady-state 1D simulations. These simulations are described and the design explained. The philosophy behind turbocharger selection, manifold tuning etc. is described in detail. After the initial design the engine was optimized for transient response. Measurement data from steady state measurements on the dynamometer is showed for verification as well as pressure data logged in the car on the racetrack.

The paper treats pulsating flow through the turbine of SI-engine turbochargers. In engine design, 1D engine-simulations are very convenient tools for optimization and concept studies. However, they have drawbacks in certain areas. The accuracy, when predicting turbocharger turbine power, is lower than desired. The reason for that is a lack of knowledge about the phenomenon of pulsating flow through the turbine. The background to the problem is described in the paper. This investigation aims at learning more about this unsteady, pulsating flow, on the engine. The method used is to do large parameter changes to several parameters in turbine and manifold designs such as A/R and trim in the turbine and also volume and length of the exhaust manifold. For selection of A/R and trim, as well as an aid in the analysis of measured data, the meanline turbine design software Rital from Concepts NREC [1] was used. Three different turbines were investigated, all with the same mass flow capacity.